The invention relates to a method and an installation for the mechanical production of horizontally divided flaskless sand molds made up of a cope (used herein to denote the top part of a mold) and a drag (used herein to mean the lower part of a mold). It constitutes a further development of the invention disclosed in U.S. Pat. No. 4,586,555.
This mold making installation is equipped with a vacuum mold blowing machine, on which the compacted masses of sand forming the drags and copes are produced alternately using a seqential controller. For this purpose the single station mold making machine possesses a mold frame, which is made up of a lower and an upper flask and a hollow pattern plate carrier, able to be inverted in the mold making station and which is divided by a horizontal partition into two chambers and on both sides is fitted with the pattern plates for the lower and upper components of the block mold, i.e. the masses of compacted sand forming the drag and cope. During the production of the drag the empty cope or upper flask is placed over the drag or lower flask and surrounds the lower end of the sand bin which is able to be shut off at its lower end by a blowing and pressing grid. Prior to the ensuing production of the cope the lower flask with the drag therein is moved out of the mold making station and simultaneously inverted and deposited in a core insertion station, from which, after the lifting of the cope clear of the pattern plate it is moved back into the mold making station. In the mold making station the upper flask is then lowered onto the lower flask and the assembled mold is stripped and then sent on its way along a casting and cooling line.
Although this mold making machine was intended to have a low overall height, this aim was not satisfactorily achieved owing to the placing of the machine flasks vertically over each other in the starting and final positions and to the necessary clearance for the inversion fo the block-shaped pattern plate carrier with patterns on both sides thereof. Furthermore, in many cases, the time allowed for core insertion is not sufficient because such time is dependent on that needed for producing the cope.
Although it is true that the core insertion time might be prolonged without prolonging the cycle time for the production of the cope if the core insertion station of such a mold making machine were designed in the form of a turntable or conveyor loop with four straight sides, in the case of such a mold making installation it would then be necessary to multiply the number of lower flasks to correspond to the number of deposit positions on the core insertion station so that the initial plant costs would be considerably increased.